This invention is concerned with a process for producing a high quality, spray-dried orange juice powder. It specifically pertains to a combination of unique spray drying parameters which yield a free-flowing orange juice powder having superior organoleptic characteristics.
Spray drying has long been advocated as a process for commercially dehydrating food materials. Such products as instant coffee, soluble tea, nonfat milk and powdered egg are produced by this technique. The process has gained favor because: (1) rapid drying rates reduce the contact time between heat sensitive foods and heating medium, (2) commercial dryers have high product throughputs, (3) product characteristics are appealing and (4) spray drying is an efficient and relatively inexpensive process.
Although spray drying is a successful technique for drying many foods, its use in connection with fruit and vegatable materials has met with very limited success to date. Spray dried fruit and vegetable materials, such as orange juice powder, being highly heat sensitive and hygroscopic, cause difficulty, not only in handling the final product, but in the drying operation itself. For example, if orange juice powder is collected at a temperature above its sticky point, the powder coalesces. Coalescing also results if the dried product reabsorbs excessive moisture from the dryer outlet air stream. At inordinately high dryer air temperatures, heat damage is inflicted on the product. If undried powder impinges on the dryer wall or the wall temperature exceeds the sticky point temperature of the juice, a build up of powder is experienced. Thus far, these problems have not been solved for a pure orange juice product--the end result has inevitably been a sticky, caked product and/or a plugged dryer.
One proposed solution has been the use of food grade, water-dispersible protective colloids, e.g., dextrins, as drying aids. In the case of orange juice, commercially-available powders have included rather large colloid quantities, i.e., in excess of 50% by weight. While such quantities mitigate dryer plugging and product coalescing, the colloids are expensive and add a perceptible off taste which dilutes the organoleptic quality of the product.
Thus, there remains a need for a feasible, economical process for producing a free-flowing, spray-dried orange juice powder of superior quality.